Improvement in artificial teeth



UNITED STATES PATENT OFFICE.

THOMAS ALDER DICKSON FORSTER, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN ARTIFICIAL TEETH.

Specification forming part of Letters Patent No. 120,509, dated October31, 1871.

To all whom it may concern:

Be it known that I, THOMAS ALDER DIOKSON FORSTER, now of Philadelphia,county of Philadelphia, State of Pennsylvania, but formerly of St.Georges, Bermuda, West India Islands, have invented certain new anduseful Improvements in Artificial Dentures, of which the following is aspecification:

My invention relates to artificial dentures, having porcelain teeth andnon-metallic composition bases; and my improvements consist in the useof a peculiar material for the base, whereby the necessity of employingheat in the manufacture of the articles is avoided, and in theapplication to the exposed parts of the base of an enamel which impartsto the same a gum color, and renders the use of gum-teeth unnecessary.

Artificial dentures consisting of porcelain teeth and non-metalliccomposition bases are objectionable for two reasons: First, in applyingor securing the base material, while plastic, to the teeth, it isnecessary to subject the com position to pressure between molds and tomain tain the whole in a heated state for the purpose of preserving theplasticity of, or to soften or to harden, the material, this heatinginvolving manipulation, which is always troublesome and in manyinstances expensive and dangerous. Second, owing to the nature of thesubstances and compositions hitherto employed, it has been difficult toimpart to them a color similar to that of the natural gum, rendering itnecessary to use what are termed gum-teeththat is, teeth withprojections at the top, formed and colored to resemble the natural gum.These teeth must be ground at the side edges and fitted together, aredifficult to secure to the base, expensive, and, owing to the numerousjoints, are otherwise objectionable.

I employ as a base a material which can be molded while cold, thematerial being oxychloride of zinc. The teeth are mounted on wax orgutta-percha in the usual manner, and are embedded in plaster formedinto a two-part mold. The wax is removed, and a composition of oxide andchloride of zinc combined, in such proportions as to form a plasticmass, is inserted in the place of the wax. The two parts of the mold arethen pressed together, and retained until the material has hardened.

In some instances other substances, as finelyground silex, may be addedto the base to give body to the same, and the plate or base may bebacked by a thin metallic or other plate, or it may be coated with asuitable enamel to prevent any disagreeable or injurious efi'ect fromdirect contact of the base with the membrane of the mouth.

As the color of the base differs from that of the natural gum, I applyto the exposed part of the base, above the teeth, an enamel, consistinggenerally of a solution of gun-cotton in ether, or its equivalent, andearmine or other suitable coloringanatter, the base, prior to theapplica' tion of the enamel, being coated with a solution of gumsandarae in alcohol and ether. By thus enameling the exposed part of thebase, the necessity of employing gum teeth is avoided, single plainteeth without gums being used, the fangs being imbedded in the base. Thesame effect with like advantage may be obtained by the application ofenamel to the exposed parts of rubber, celluloid, or other similarbases, it only being necessary to employ as a liquid vehicle for thecoloring material a solvent of the material composing the base.

To prevent the shrinking of the enamel in drying, it is well to add tothe solution a solution of sandarae, eopal, or other suitable gum.

When a collodion base is employed, it is well to coat the whole surfacewith enamel, as it prevents the disagreeable smell and taste arisingfrom the presence of camphor, and obviates the necessity of polishing.

I claim as my invention- 1. An artificial denture, consisting ofporcelain teeth mounted on a base, composed in whole or in part ofoxychloride of zinc, as set forth.

2. An artificial denture, in which single plain teeth are imbeddcd in abase consisting of a composition of the character described. and whichsurrounds the fangs and forms the gum, as set forth.

3. An artificial denture, in which the gum or surface of the base abovethe teeth is coated with enamel, applied as specified.

In testimony whereof I have signed my name to this specification in thepresence of two sub scribing witnesses.

T. A. D. FORSTER. Witnesses:

CHARLES E. FORSTER,

JOHN K. RUPER'rUs. (46)

